Synthesis and crystal structures of 2-bromo-1,3-dimethylimidazolium iodides

Abstract

Attempts at direct bromination of 1,3-dimethylimidazolium salts were futile. The title compounds, 2-bromo-1,3-dimethylimidazolium iodide chloroform 0.33-solvate, C5H8BrN2+·I−·0.33CHCl3, 2-bromo-1,3-dimethylimidazolium iodide dichloromethane hemisolvate, C5H8BrN2+·I−·0.5CH2Cl2, and 2-bromo-1,3-dimethylimidazolium iodide hemi(diiodide), C5H8BrN2+·I−·0.5I2, were obtained by methylation of 2-bromo-1-methylimidazole. They crystallized as CHCl3, CH2Cl2 or I2 solvates/adducts. The Br atom acts as a σ-hole to accept short C—Br...I interactions. C—H...I hydrogen bonds are observed in each structure.

Keywords

• crystal structure
• bromo
• chloroform
• dichloromethane
• imidazole
• iodide